That's actually a vast improvement already @rjen, bringing the icon inside like that makes things more compact.
Looking at your posts (on your live test site) with the attachment displaying as the icon, that looks nice too. Only wish in some way it could pick up the first image embedded as an alternative, much like OG (Open Graph) does. This would also make it usable when sharing those posts on Social Media,
I'm pretty sure that OG doesn't pick up the attachment, but does pick up the first image in the post as a thumbnail. That basically means, if you share a post and also want a custom icon you have to have an attachment for your icon, and a embedded image for sharing the post so OG can add the thumbnail.